Holding(s) in Company

Pennon Group PLC
31 January 2007

PENNON GROUP PLC


FOR IMMEDIATE RELEASE


HOLDING IN COMPANY




NOTIFICATION OF MAJOR INTERESTS IN SHARES


1. Identity of the issuer or the underlying issuer of existing shares to which
voting rights are attached



PENNON GROUP PLC.



2. Reason for the notification



An acquisition or disposal of voting rights



3. Full name of person(s) subject to the notification obligation



   (1)     Lansdowne Partners Limited being the General Partner of Lansdowne
           Partners Limited Partnership

   (2)     Lansdowne UK Equity Fund Limited

   (3)     Landsdowne Partners International Limited



4. Full name of shareholder(s)



Morstan Nominees Limited (Registered Shareholder)



5. Date of the transaction (and date on which the threshold is crossed or
reached if different)



29 January 2007



6. Date on which issuer notified:



31 January 2007



7. Threshold(s) that is/are crossed or reached:



3%



8. Notified details:









A: Voting rights attached to shares


Class/type of shares if possible              Situation previous to the Triggering transaction
using the ISIN CODE
                                  Number of shares                   Number of voting Rights
Ordinary
                                  14,917,426                         14,917,426



Resulting situation after the triggering transaction


Class/type of shares if      Number of shares         Number of voting rights           % of voting rights
possible using the ISIN CODE
                             Direct                   Direct       Indirect             Direct      Indirect

  Ordinary                                                                               
                                 0                           0      14,102,965            0.0%       3.96%





B: Financial Instruments

Resulting situation after the triggering transaction (xii)


Type of         Expiration Date       Exercise/Conversion       Number of voting rights     % of voting rights
financial       (xiii)                Period/ Date (xiv)        that may be acquired if the
instrument                                                      instrument is exercised/
                                                                converted.






Total (A+B)
Number of voting rights        % of voting rights


14,102,965                     3.96%



9. Chain of controlled undertakings through which the voting rights and/or the
financial instruments are effectively held, if applicable :



Lansdowne Partners International Limited is the parent undertaking of Lansdowne
Partners Limited.



Proxy Voting:



10. Name of the proxy holder:



Lansdowne Partners Limited



11. Number of voting rights proxy holder will cease to hold:





12. Date on which proxy holder will cease to hold voting rights:



13. Additional information:



   (1)    Lansdowne Partners Limited being the General Partner of Lansdowne
          Partners Limited Partnership (LPLP) controls 14,102,965 voting rights
          representing 3.96%


   (2)     Lansdowne UK Equity Fund Limited owns 13,425,084 voting rights
           representing 3.77%



            The balancing 0.19% of shares is held on behalf of other client
            funds managed '           by LPLP



Annex to Notification Of Major Interests In Shares



A: Identity of the person or legal entity subject to the notification obligation



Full name (including legal form for legal entities):



Pennon Group Plc



Contact address (registered office for legal entities):



Peninsula House, Rydon Lane, Exeter, Devon, EX2 7HR



Contact name Margaret Lilian Heeley

Assistant Company Secretary



Phone number 01392 443060











31 January 2007



www.pennon-group.co.uk



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